1. Technical Field Text
This application relates to the use of one or more parasympathomimetic drugs or a cholinesterase inhibitor in combination with one or more alpha agonists or antagonist to create optically beneficial miosis to, for example, temporarily treat presbyopia.
2. Background Information
Presbyopia is typically age-related eye deterioration. Young, properly functioning, eyes are able to see at near distances, an ability that deteriorates as one ages. Presbyopia normally develops as a person ages, and is associated with a natural progressive loss of accommodation. A presbyopic eye loses the ability to rapidly and easily focus on objects at near distances. Presbyopia progresses over the lifetime of an individual, usually becoming noticeable after the age of 45 years. By the age of 65 years, the crystalline lens has often lost almost all elastic properties and has only limited ability to change shape.
Use of over the counter reading glasses is a very common way of addressing the vision problems associated with presbyopia. Reading glasses allow the eye to focus on near objects and maintain a clear image. This approach is similar to that of treating hyperopia, or farsightedness.
Many presbyopes are also prescribed bi-focal eyeglasses, where one portion of the lens is corrected for distance vision and another portion of the lens is corrected for near vision. When peering down through the bifocals, the individual looks through the portion of the lens corrected for near vision. When viewing distant objects, the individual looks higher, through the portion of the bi-focals corrected for distance vision. Contact lenses and intra-ocular lenses (IOLs) have also been used to treat presbyopia, for example, by relying on monovision (where one eye is corrected for distance-vision, while the other eye is corrected for near-vision) or bilateral correction with either bi-focal or multi-focal lenses. Laser ablation has also been used to treat presbyopia. All these procedures seek to correct the problem for long term purposes using drastic steps (surgery, laser ablation, etc) or require wearing corrective lenses.
Thus, there remains a need for new ways of ameliorating or reducing presbyopia for patients that do not wish to undergo surgery (IOLs, laser ablation, etc.) or use corrective glasses. For people who use corrective lenses, there remains a need to temporarily treat presbyopia without the use of corrective lenses.